Leaf's vein is a term used to describe the network of veins that are found in the leaves of plants. The term is also known as the venation pattern, and it is important for the plant's ability to transport nutrients and water throughout its body. The crossword solution for Leaf's Vein is 'RIB', which is an acronym for 'Radial Intercostal Bundle'. This bundle is a network of veins that run along the midrib of the leaf, connecting the veins that run along the edges of the leaf.